It's 15-18 inches long, only 1/2-3/4 inch diameter. Red but not bright red (but he might be a little dirty) and smaller tan rings separated by thinner black - so, black-red-black-tan-black-red....
If he's a corn snake, maybe it's not really rings, and he'll grow into his spots.

Found this pretty fellow in the yard. Very feisty - didn't hesitate to attack a small stick held near it! I'm not sure of king snake IDs...

(sorry about the grainy photo - it's a frame from a digital movie)

I spent much of spring, 2006, on a private ranch near McCook, Texas while participating in a wildlife photo contest. This species was seen several times per week at night along roads or near the house I was staying in. I photographed several individuals in these months.